Prenatal growth of the human vomeronasal organ

Abstract

Background: Vomeronasal organs (VNOs) are paired epithe-lial structures located adjacent to the nasal septum that form in the late first trimester of human fetal development. Although VNOs have long been known to exist in fetal and adult humans, some studies continue to suggest that these structures may be degenerative or functionless. Little is known of the growth of the VNO. Methods: The present study examined length and volume changes of the human VNO in 26 ''normal'' (10 female, 16 male) histologically prepared fetuses from the University of Pittsburgh and the University of Michigan across three trimesters (8-30 weeks postmenstrual age). A computer reconstruction technique was used to quantify lengths and volumes of right and left VNOs, and regression equations were generated to assess growth rates. Results: A linear increase in VNO length and a logarithmic increase in VNO volume with increasing postmenstrual age was found. Volume increase was noted for both the vomeronasal epithelium and the lumen of the VNO. A comparison with most estimates of adult human VNO length suggested that further prenatal or postnatal size increase occurs. The growth curves also suggested a more rapid growth in VNO length and volume for females than for males. Conclusions: The present study demonstrates that the fetal human VNO commences volumetric increase in the early second trimester but does not achieve maximum size during fetal development. Further investigation is needed to determine whether the human VNO is sexually dimorphic in size. Anat.

Reappraisal of the vomeronasal system of catarrhine primates: Ontogeny, morphology, functionality, and persisting questions

“…The result is an anteroposteriorly oriented epithelial tube (Figs. 3E, 4B) that increases in length and volume during the second and third trimesters of fetal development (Smith et al, 1997). Before elevation of the palatal shelves, nearly all mammals seem to possess this anteroposterior tube that communicates with the nasal cavity (Wöhrmann‐Repenning and Ciba, 1989; Smith and Bhatnagar, 2000).…”

The vomeronasal organ of greater bushbabies (Otolemur spp.): Species, sex, and age differences

“…Still fewer studies examined sexual dimorphism of primate VNOs. Several studies examined VNO size in prenatal humans (Sherwood et al, 1999;Smith et al, 1996Smith et al, , 1997 and mouse lemurs (Smith et al, 2001b). Only the human VNO was quantified in a large sample of adults, but no significant length differences were found between sexes (Abolmaali et al, 2001).…”

Morphological Studies Of Vomeronasal Organ In The Wild Juvenile Red- Flanked Duiker Cephalophus rufilatus (GRAY 1864)

“…The palatine and vomer bones were trimmed and the VNO dissected out from the tissues by sawing with small hand saw. These blocks of tissue containing the VNO was fixed in 10% neutral buffered formalin, decalcified using formic acidsodium citrate solution according to Bhatnagar and Kallen (1974) and Smith et al, (1997). The tissues were dehydrated in graded series of ethanol, cleared in xylene and embedded in paraffin wax.…”